The present invention relates to the decontamination arts. It finds particular application in conjunction with the sequential cleaning and microbial decontamination of medical instruments and equipment and will be described with particular reference thereto. It should be appreciated, however, that the invention is also applicable to a wide variety of technologies in which at least three components or reagents are kept separate until time of use and then sequentially released into a fluid line.
Heretofore, medical equipment and instruments have often been microbially decontaminated by sterilizing or disinfecting the equipment in a steam autoclave. Autoclaves kill life forms with a combination of high temperature and pressure. However, steam autoclaves have several drawbacks. The high temperature pressure vessels tend to be bulky and heavy. The high temperature and pressure tends to curtail the useful life of endoscopes, rubber and plastic devices, lenses, and portions of devices made of polymeric materials and the like. Moreover, a typical autoclave sterilizing and cool down cycle is sufficiently long that multiple sets of the medical instruments are commonly required.
Instruments which cannot withstand the pressure or temperature of the oven autoclave are often microbially decontaminated with ethylene oxide gas, particularly in larger medical facilities or hospitals. However, the ethylene oxide sterilization technique also has several drawbacks. First, the ethylene oxide sterilization cycle tends to be even longer than the steam autoclave cycle. Another drawback is that ethylene oxide sterilization is sufficiently sophisticated that trained technicians are commonly required, making it unsuitable for physician and dental offices and for other smaller medical facilities. Moreover, some medical equipment can not be sterilized with ethylene oxide gas.
Liquid microbial decontamination systems have recently been utilized for equipment which could not withstand the high temperatures of steam sterilization. Commonly, a technician mixes a liquid disinfectant or sterilant composition and manually immerses the items to be microbially decontaminated in the composition. The high degree of manual labor introduces numerous uncontrolled and unreported variables into the process. There are quality assurance problems with technician errors in the mixing of sterilants, control of immersion times, rinsing of residue, exposure to the ambient atmosphere after the rinsing step, and the like.
Moreover, it has recently come to light that items which have been throughly sterilized may nevertheless be contaminated with biological materials. Although sterile, these materials may break down and be converted to toxins which are hazardous to patients on which the instruments are used. Additionally, the presence of biological materials on the items reduces the efficiency of the sterilization process because the biological materials inhibit the access of the decontaminant to the microorganisms. To reduce the amounts of these toxin-producing residues and provide for more effective sterilization, items are now frequently cleaned before sterilization or disinfection. The separate cleaning step, however, can be hazardous to operators who handle the cleaned instruments and transfer them from the cleaning bath to the sterilizer.
To deliver reproducible amounts of sterilants to the microbial decontamination system, a number of packaging systems have been developed. One problem to overcome is that cleaning agents, such as detergents, and pretreatment agents, such as buffers and corrosion inhibitors, tend to degrade peracetic acid. Combining them with liquid peracetic acid results in an unacceptably short shelf life. Thus, for peracetic sterilants, in particular, such components of a treatment system are generally kept separate to prolong shelf life. U.S. Pat. No. 5,037,623 to Schneider, et al., for example, discloses a cup which contains a measured dose of a liquid peracetic acid concentrate. Buffers, detergents, and anticorrosive agents, in the form of a powder, are separately contained. The cup includes a linear vent passage which extends into the interior of the cup. A gas permeable membrane is mounted over the interior end of the vent passage to allow venting of the container during storage. The cup is only partially filled with sterilant liquid such that the top surface of the liquid is always below the vent aperture, irrespective of the orientation of the cup.
U.S. Pat. No. 5,662,866 to Siegel, et al. discloses a two-compartment cup for powdered sterilant reagent components. An outer compartment holds a first reagent while an inner compartment, disposed within the outer compartment, holds a second reagent. In the case of peracetic acid, the two reagents react in water to form peracetic acid. Pretreatment agents may be included in one of the two compartments. Peripheral walls of inner and outer cups are affixed together at flanges adjacent their open ends to define the two compartments. A permeable sheet is affixed to the inner cup flange for ventedly sealing both cups. The outer cup is closed at its base by a first detachable base and the inner cup similarly closed by a second detachable base.
To release the sterilant into the fluid flow path of a microbial decontamination system, the cup is inserted into a well in fluid communication with the system. In the case of the liquid sterilant cup, a peel-off top is removed to provide access to the contents of the cup. Alternatively, a cutter, such as that disclosed in U.S. Pat. No. 5,439,654 to Kochte, pierces the base of the cup with a blade. Jets of water are sprayed into the cup to dissolve and flush the sterilizing agents from the cup. In the case of the powdered sterilant cup, pressure is applied to detach the bases of the inner and outer cup portions.
The measured dosage cups, while improving sterilization assurance with a reproducible, pre-measured dose of reagents, release the entire contents of the cup into the microbial decontamination system at the same time. There is no provision for sequential release of other components, such as cleaning agents, corrosion inhibitors, buffers, and the like. Although such components may be included in the measured dosage cups, their effectiveness is less than if used as pretreatments. Because these are released into the system at the same time as the sterilant, they do not have time to circulate through the microbial decontamination system prior to addition of the sterilant. In the case of inhibitors, for example, their function is to provide protection for the system and items to be sterilized against the corrosive components of the sterilant. By releasing inhibitors at the same time as the sterilant, the sterilant has the opportunity to corrode metal parts before the inhibitors have developed protective barriers around the parts. In the case of buffers, their function is to modify the pH of the fluid circulating in the system so that the pH is optimal for sterilization. Until the buffer has circulated throughout the system, the sterilant is not fully effective. Additionally, such agents may degrade the sterilant during storage.
The present invention provides for a new and improved multi-compartment packaging assembly and sequential cutter which overcome the above-referenced problems and others.
In accordance with one aspect of the present invention, a combined system for selectively cleaning and microbially decontaminating items is provided. The system includes a receiving well for receiving a container which separately contains at least a first treatment material and a second treatment material, the first treatment material including a cleaning agent, the second treatment material including a microbial decontaminant. A sequential delivery assembly sequentially releases the first treatment material and the second treatment material from the container. A first fluid flow path is defined between a water receiving inlet and the well for supplying water from the inlet to the well to mix with the first and second treatment materials to form a treatment fluid. The treatment fluid sequentially includes the first treatment material and the second treatment material. A second fluid flow path is defined for the treatment fluid from the well to a cleaning and decontaminating region for receiving items to be sequentially cleaned and microbially decontaminated. A fluid circulator selectively circulates fluid through the first and second fluid flow paths and among the decontamination region and the receiving well.
In accordance with another aspect of the present invention, a method of sequentially cleaning and decontaminating items is provided. The method includes opening a first compartment of a container to release a first treatment material, mixing the first treatment material with water to form a first treatment fluid, and delivering the fluid to a cleaning and decontaminating region containing the items to be cleaned and decontaminated. The items are contacted with the first treatment fluid for a period sufficient to clean substantially the items. The method further includes opening a second compartment of the container to release a second treatment material, mixing the second treatment material with a mixing fluid, which includes water, to form a second treatment fluid, and delivering the second treatment fluid to a cleaning and decontaminating region containing the items to be cleaned and decontaminated. The items are contacted with the treatment fluid for a period sufficient to decontaminate them.
In accordance with yet another aspect of the present invention, a sequential delivery system is provided. The system includes a receiving well for receiving a multi-compartment container. The container includes first, second, and third compartments, each defining a peripheral wall, which receive first, second, and third materials, respectively. A sequential cutter selectively cuts the first, second, and third peripheral walls. A fluid flow path in fluid communication with the sequential cutter selectively delivers a dilution fluid to the first, second, and third compartments to flush out the first, second, and third materials.
In accordance with another aspect of the present invention, a three compartment cup for use in a decontamination system of the type which includes a decontamination chamber for receiving items to be cleaned and decontaminated and a decontaminant receiving well in fluid communication with the chamber, is provided. The cup includes first, second, and third cup portions, each including a peripheral wall which define first, second, and third compartment. First, second, and third treatment materials are disposed in the three compartments. The first treatment material includes a cleaning material, the second treatment material including a pretreatment material for preparing the decontamination system for receiving a decontaminant. The decontaminant is disposed in the third compartment. The first, second, and third compartments are configured for sequential opening of the first, second, and third peripheral walls.
One advantage of the present invention is that it facilitates materials handling.
Another advantage of the present invention is that it simplifies filling and sealing of cleaning agents, sterilizing reagents, and pretreatment reagents in separate compartments.
Yet further advantages of the present invention derive from the sequential cleaning and sterilization of items in a single system.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.